The overall objective of this investigation is to elucidate the biochemical mechanisms by which angiotensin II exerts its biological effect on responsive tissues. In vitro techniques will be used to study the interaction of angiotensin II with a specific hormone receptor in rat adrenal glomerulosa cells. Labeled angiotensin II with be incubated with subcellular fractions of adrenal capsular homogenates, or with metabolically actice glomerulosa cell suspensions. Qualitative and quantitative data will be obtained on the nature of the binding substance, the specificity and kinetic parameters of the interaction and the amount of specific angiotensin II receptor present in different cell types. Comparisons will be made between normal adrenal cells and those obtained from animals with certain types of experimental hypertension. The relationship between hormone binding and adenyl cyclase activity will be studied. Attempts will be made to obtain data on angiotensin receptors in vascular smooth muscle, and this data will be compared and contrasted with that of the adrenal gland.